Variable inertia launch ramp

ABSTRACT

A launch ramp includes a hollow body having first and second ends and upper and lower walls which converge to a relatively sharp edge at the first end of the body. Support legs are mounted to the body adjacent to the second end thereof, the legs being extendable an appreciable distance from of the bottom wall so that when the edge and the legs rest on a horizontal surface, the top wall is inclined at an appreciable angle relative to that surface. The hollow body defines a fluid-tight chamber which may be filled with a fluid substance to change the weight, inertial characteristic and stiffness of the ramp body.

BACKGROUND OF THE INVENTION

[0001] This invention relates to launch ramps for use by bikers, skateboarders and rollerbladers. It relates especially to a launch ramp which is foldable so that it is portable and which has a variable inertia characteristic.

[0002] A launch ramp is a rigid inclined structure which when approached by bikers, skateboarders and rollerbladers can launch those individuals into the air so that they can perform various acrobatic feats before dropping back to the ground. The prior ramps of this type are invariably relatively bulky because the upper end of the ramp must have appreciable elevation in order to be able to launch the riders into the air. Consequently, the prior ramps occupy relatively large amounts of shipping and storage space. Furthermore, it is not particularly easy to move them from place to place.

[0003] Additionally, conventional launch ramps of this general type tend to slide along the ground when engaged by the wheels of the moving bike or skateboard. If the ramp is situated on the ground, such sliding can be minimized by anchoring the ramp to the ground by driving nails or pegs through the edges of the ramp into the ground. However, that solution to the sliding problem is not feasible when the ramp is situated on a paved street or sidewalk.

[0004] Also, the launching characteristics of conventional ramps are fixed and determined by the shape and flexibility of the ramp. Therefore, while a given ramp might be suitable for launching a skateboarder of a given weight, it may not effectively launch a heavier person on a bicycle. It would be desirable, therefore, to be able to provide a launch ramp whose launch characteristics can be changed to some extent to suit the particular user.

SUMMARY OF THE INVENTION

[0005] Accordingly, it is an object of the present invention to provide an improved launch ramp for bikers, rollerbladers and skateboarders.

[0006] Another object of the invention is to provide such a launch ramp which is foldable so that it can be carried about readily from place to place.

[0007] A further object of the invention is to provide a launch ramp of this general type which can be shipped and stored in a minimum amount of space.

[0008] Still another object of the invention is to provide a launch ramp whose weight can be varied.

[0009] A further object of the invention is to provide a launch ramp which resists sliding along the ground when in use.

[0010] Still another object of the invention is to provide a launch ramp whose inertial characteristic may be changed to suit a particular application and user.

[0011] Other objects will, in part, be obvious and will, in part, appear hereinafter.

[0012] The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.

[0013] In general, the launch ramp comprises a double walled ramp body having a hollow interior that constitutes a fluid-tight chamber. The front of the body tapers to a relatively sharp edge while the opposite or rear end of the body is relatively thick and is supported above the ground by a leg structure which, when the ramp is not in use, may be folded against the underside of the ramp body. In that folded condition, the ramp can be shipped and stored in a minimum amount of space and may be carried about easily from place to place. As we shall see, a special handgrip is built into the ramp body to facilitate carrying the folded ramp.

[0014] It is a feature of the invention that a fill opening is provided in a wall of the ramp body so that the hollow interior of the body can be filled with a fluid substance such as sand or water to vary the weight of the ramp and thus its inertial as well as its flexing characteristics. By varying the amount and type of fill in the ramp body, the sliding and launching characteristics of the ramp may be varied to suit the particular surface on which the ramp is placed and the particular person using the ramp, e.g. a relatively light weight rollerblader versus a larger, heavier biker.

[0015] As we shall see, the ramp is relatively inexpensive to make in quantity and it is relatively easy to assembly by the ultimate purchaser. Therefore, it should prove to be a highly marketable play item.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanied drawings, in which:

[0017]FIG. 1 is a side elevational view of a launch ramp incorporating the invention showing the launch ramp ready for use by skateboarders, bikers or rollerbladers;

[0018]FIG. 2 is a rear elevational view with parts broken away thereof, and

[0019]FIG. 3 is a bottom plan view showing the launch ramp in its folded condition, when stored and carried about.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] Referring to FIGS. 1 and 2 of the drawings, the subject launch ramp comprises a ramp body shown generally at 10 supported at one end by a foldable leg structure indicated at 12. Body 10 has a gently curved, i.e. concave, upper wall 10 a, a lower wall 10 b, is a pair of mirror image side walls 10 c, 10 c, and rear end wall 10 d. Walls 10 a and 10 b are relatively far apart at the upper or rear end of body 10 and they converge toward the front of the body where the two walls meet at a relatively sharp leading edge 14 adapted to rest next to the ground. Preferably, the lower wall 10 b is flattened or tapered adjacent to edge 14 so that is forms a substantially horizontal surface 15 which can rest flat on the ground or other support surface. Preferably, that surface 15 is treated so as to increase its coefficient of friction. For example, surface 15 may be knurled or covered with rubber or other non-slip material.

[0021] Preferably also, the lower wall 10 b of body 10 is formed with a plurality of laterally spaced apart ribs 16 which extend between the ends of body 10 and serve to stiffen the body. Also formed in lower wall 10 b adjacent to rear wall 10 d is a recessed handgrip 18 (FIG. 3) which facilitates carrying the folded ramp from place to place.

[0022] As shown in FIG. 2, the walls 10 a to 10 d of body 10 define a fluid-tight interior compartment or chamber 20. This chamber may be accessed by way of a fill opening 22 in one of the body walls, e.g., rear wall 10 d, so that the chamber 20 can be filled with a fluid substance such as water W as shown in FIG. 2 or with particulate material such as sand. Fill opening 22 may be closed by a fill cap or plug 24.

[0023] Referring to FIGS. 1 and 3, the foldable leg structure 12 is formed by a generally U-shaped tube or rod 32 having a pair of legs 32 a, 32 a connected at corresponding ends by a bridging portion 32 b. Preferably the free ends of legs 32 a, 32 a are covered by nonslip plastic or rubber feet 34. As best seen in FIG. 3, the bridging portion 32 b of tube 32 is recessed into a transverse channel 36 in the lower wall 10 b of the ramp body 10 near wall 10 d and rotatably retained there by a pair of plates or brackets 38, 38 secured by suitable fasteners 42 to the lower wall 10 b just inboard from tube legs 32 a, 32 a. Thus, legs 32 a, 32 a are able to be swung between an extended or open position shown in solid lines in FIGS. 1 and 2 wherein the free ends of the legs extend appreciably below ramp body 10 and a folded position illustrated phantom in FIG. 1 and in FIG. 3 wherein the legs 32 a, 32 a are folded flat against the wall 10 b of body 10.

[0024] The extended or open position of the legs as shown in FIG. 1 is established by the engagement of the upper end segments of legs 32 a, 32 a against stopping surfaces 46 formed in lower wall 10 b just outboard from plates 38. As shown in FIG. 3, the surfaces 46, 46 are aligned with legs 32 a, 32 a so that when those legs are swung to their extended position shown in FIG. 1, the legs engage surfaces 46, 46. Preferably as shown in FIG. 1, the legs 32 a, 32 a are bent to form knees 32 c just below body 10 so that a downward force on body 10 tends to urge the legs against surfaces 46, 46 adding stability to the ramp.

[0025] Preferably the ramp body 10 is blow molded of a strong, impact resistant, weather resistant plastic material such as polyethylene. A typical ramp may be 25 inches wide, 37 inches long and 12 inches high when legs 32 a, 32 a are extended as in FIG. 1, and 4 inches high when the legs are folded as shown in FIG. 3. Typically the foldable leg structure 12 is of steel.

[0026] When the launch ramp is being carried about using handgrip 18 or when stowed away, the chamber 20 may be empty of contents and the leg structure may be in its folded condition as in FIG. 3. When it is time to use the ramp, it may be placed on the ground as shown in FIG. 1 and the body 10 filled with a fluid such as water or sand to increase its weight and thereby adjust the inertia of the launch ramp as a whole. The filling of body 10 also changes the stiffness of the body to some extent and thus enables one to alter the launch characteristics of the ramp to suit a particular application or user.

[0027] It will thus be seen that the objects set forth above among those made apparent from the preceding description are efficiently attained. Also, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

[0028] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention described herein. 

1. A launch ramp comprising a hollow body having first and second ends and upper and lower walls which converge to a relatively sharp edge at said first end of the body, and support means mounted to said body adjacent to the second end thereof, said support means being extendable an appreciable distance from of said lower wall so that when said edge and said support means rest on a horizontal surface, said upper wall is inclined at an appreciable angle relative to said surface.
 2. The ramp defined in claim 1 wherein said hollow body has additional walls extending between said upper and lower walls so as to define a fluid-tight chamber in said body; an opening through one of said walls into said chamber, and closure means for said opening.
 3. The ramp defined in claim 2 and further including a fluid substance at least partially filling said chamber so as to increase the weight of said body.
 4. The ramp defined in claim 3 wherein said fluid substance is a liquid.
 5. The ramp defined in claim 3 wherein said fluid substance is particulate material.
 6. The ramp defined in claim 3 and further including means defining a handgrip in said lower wall adjacent to an end of the body.
 7. The ramp defined in claim 1 wherein said upper wall, in profile, has concave curvature.
 8. The ramp defined in claim 7 wherein said lower wall has stiffening ribs extending between said body ends.
 9. The ramp defined in claim 1 wherein said support means comprise a pair of parallel legs, and means for movably mounting said legs to said bottom wall so that said legs can be moved between a folded position wherein the legs are nested against and extend generally parallel to said bottom wall and an extended position wherein said legs extend out at a substantial angle to said bottom wall.
 10. The ramp defined in claim 9 wherein the mounting means include means which, when the legs are in their extended position, cause said legs to protrude at an obtuse angle from the bottom wall.
 11. The ramp defined in claim 10 wherein said legs are bent to form knees therealong which point away from said edge. 